Vegetation
Canopy Lidar (VCL)
-Data Products-
Vegetation
Canopy Lidar (VCL)
There are two basic types of data products delivered by VCL: gridded and ungridded (see Table 1). The ungridded data products are the along-track, contiguous footprint observations. The ungridded data products consist of calibrated waveforms and ranges, should users wish to derive their own parameters from the lidar measurements (Level 1B), and data products derived from these (Level 2), but using VCL developed algorithms. These Level 2 products consist of geolocated measurements of canopy top heights, ground height, and the vertical distribution of intercepted surfaces.
VCL provides products gridded at two different spatial and temporal
resolutions: 1° monthly products and 4 km products at 6 month intervals.
These time periods are function of the revisit times to any particular
cell for the given spatial resolution. During a one month period, VCL visits
a 1° grid cell at the equator twice (with more frequent visits away
from the equator). Every month the derived Level 2 parameters accumulated
for a cell are gridded and released as Level 3 products (see Table 1).
Similarly, every 6 months the accumulated Level 2 data for a particular
4 km grid cell are gridded and released as a Level 3 product, the longer
time period being needed to accumulate enough returns for the smaller area.
An additional Level 3 data set, 4 km fractional forest coverare also derived
from these observations. Every 6 months these 4 km grids will be updated
with the accumulated returns.
|
VCL Data Set Levels and Descriptions |
||
|---|---|---|
| Level | Description | Estimated Data Volume |
| 0 | Uncompressed instrument data | 5.0 Gb/day |
| 1A | Orbital, calibration and time parameters inserted | 5.0 Gb/day |
| 1B | Calibrated waveforms and ranges | 6.0 Gb/day |
| 2 | Geolocated canopy top heights | 0.5 Gb/day |
| Geolocated vertical distribution of intercepted surfaces | 6.0 Gb/day | |
| Geolocated ground heights (including sub-canopy) | 0.5 Gb/day | |
| 3 | Gridded mean canopy top height and variances (1 deg by 1 deg) | 0.4 MB/month |
| Gridded median height of intercepted surfaces (1 deg by 1 deg) | 0.2 MB/month | |
| Gridded mean ground height and variances (1 deg by 1 deg) | 0.4 MB/month | |
| Gridded mean canopy top height and variances (4 km) | 130 MB/6 months | |
| Gridded median height of intercepted surfaces (4 km) | 65 MB/6 months | |
| Gridded mean ground height and variances (4 km) | 130 MB/6 months | |
| Gridded fractional forest cover (4 km) | 32 MB/6 months | |